Picture this: you are driving along when, out of the blue, your car’s transmission starts acting up. The “check engine” light comes on, telling you that there is a problem. At the same time, your car’s transmission automatically shifts into second or third gear and stays there.
What Transmission Do I Have?
Limited to one gear and 30-45 mph, you know there is a serious problem with your car’s transmission and you have to get your car to either your dealer or transmission repair shop to have the problem diagnosed and repaired.
Naturally, the first questions that go through your head are: Why did this happen? How severe is it? and How much will it cost to fix?
In This Guide
- What Causes Limp Mode?
- Limp Mode’s Protective Actions
- Example Situation
- How the Computer Determines That a Sensor is Incorrect
- What You Should Do
- Questions to Ask Yourself
What Causes Limp Mode?
Today, nearly every system in your vehicle is operated by the computer – including the transmission’s line pressure, shift timing, sequence and feel. The vehicle speed sensor provides input to help control ABS, fuel mixture, fuel injection and transmission operation. The manifold absolute pressure (MAP) sensor and throttle position sensor (TPS) provide the engine’s load information which is used to manage the shift and downshifting in the transmission when you’re driving up an incline or you’ve put the pedal to the metal.
Fail Code conditions or “Limp Mode” occurs when there is a problem with the logic of a vehicle’s computer. When the signal value sent by a sensor to the computer is not within a pre-programmed range specified by the manufacturer, it will switch to “secondary” programming. These procedures are designed to protect the transmission from further damage that could be caused by the signal error.
As long as the computer is receiving signals from the MAP, TPS, vehicle speed and other sensors that fall within their “normal” ranges based on the current conditions, the transmission will operate normally. However, as mentioned above, if it receives a signal that is outside of the expected range, it will switch to secondary/emergency operation.
The exact measures taken in secondary operation is determined by the computer’s logic as programmed by the manufacturer and depends on how far outside the acceptable range the signal is (if there is any signal at all). It might react differently when the value is higher than the highest parameter than it does when the value is lower than the lowest allowable value.
Limp Mode’s Protective Actions
If the signal value wasn’t far enough outside of the range to indicate a mechanical failure, the first thing the computer will do is turn the check engine light on to alert the driver that they should have the vehicle checked out using a code reader/diagnostic scanner to see if there are any “soft codes” listed. Soft codes can indicate that a low priority sensor has malfunctioned or is starting to break down. If the light goes away after restarting your car, it could mean that the sensor only failed once due to a loose connection or it could be a sign that its condition is getting worse. Critical functionality is typically unaffected by this kind of problem, but if the issue isn’t resolved, it can negatively impact the performance or fuel efficiency of the vehicle.
Now, if the signal value from a high priority sensor (necessary for critical functions) is dangerously far out of the acceptable operating range, the computer switches over to secondary “survival” mode. This is known as a “hard code”. In this mode, the computer shuts off the electronic shift solenoids. This disables the transmission’s ability to shift gears and causes it to default to single usable gear – usually second or third. In addition, the pressure in the transmission’s fluid lines is set to high in order to protect the bands and clutches from being damaged. The signals that control the line pressure are set to “full on” to prevent the clutch pack from a slipping dangerously.
All of these changes result in the previously described “Limp Mode”. Instead of leaving you stranded with a broken down vehicle, it enables the vehicle to limp home or to the nearest service center for repairs while reducing the risk of doing further damage.
Example
For example, one of situations that would cause a transmission to go into limp mode is if the cable harness going to the transmission is damaged or detached. In this case, the computer would sense that it lost communication with the transmission, but since the harness is detached, the command to go into limp mode cannot make it to the transmission. However, with no power supplied to the solenoids, the line pressure is set to high and the transmission is stuck in 2nd or 3rd gear – the same effect the limp mode command would have.
How the Computer Determines That a Sensor is Incorrect
Say, for example, that the computer receives a signal from the Throttle Position Sensor (TPS) stating that the pedal is to the metal when the throttle is actually closed. It would spot this error when it compared this status with the vehicle speed sensor, which would be signaling low or no speed. As soon as it sees this discrepancy, the computer will command the transmission to go into limp mode and turn the check engine light on. A signal value by itself can’t always be classified as an error, but when analyzed with other sensor outputs, the computer can easily figure out if there is a problem.
The fault code of the sensor causing the error is recorded by the computer. A mechanic can use a diagnostic scanner or code reader to find the recorded codes and then look them up in a table from the manufacturer to determine which sensor, and therefore which system is the source of the malfunction. Many scanners are pre-programmed with these tables and return more information than just the codes.
For example, the diagnostic scanner could return the code “35”, which indicates that the problem has to do with the transmission fluid temperature sensor. The abnormal values that were recorded and the “normal” range for the sensor could also be provided to the mechanic.
It is recommended to have a vehicle’s computer scanned regularly for fault codes – especially if the check engine light is on. This is done by most service centers during routine tune-ups.
What You Should Do
If your transmission is in limp mode, your transmission has a problem and you should get it fixed as soon as possible. Here is what you should do:
- Do not panic! Limp mode is specifically designed to limit further damage and allow you to get your car to a service center
- If possible, drive directly to a service center
- Otherwise, drive home and call a service center to have your vehicle towed
- If you do not feel comfortable driving at a limited speed, pull off the road where it is safe to do so and call for a tow
- It is advised that you do not continue to drive a vehicle in limp mode as it is unsafe and can cause further damage to your vehicle
Questions to Ask Yourself
Once your vehicle is safely in the service area, it is time to answer a few questions that will help diagnose the problem:
What Transmission Do I Have?
- How fast were you driving and how long had you been driving when the problem occurred?
- Did any lights on the dash come on? Did they come on when you started the car or after driving a while? Did they stay on?
- What repairs or maintenance has been done to the vehicle in the last month?
- Have you noticed any signs of a problem recently (noises, behaviors, leaks, etc.)?
More Information by Transmission Type
Problems by Make & Model
OBD2 Transmission Trouble Codes
| DTC Code |
|---|
| P0218 |
| P0702 |
| P0705 |
| P0730 |
| P0740 |
I recently bought a 2003 ford super duty 5.4 triton pickup truck when I went to go to the store today it acted like it didn’t have any power I hadthegas petal all of the way to the floor andwould slowly accelerate and when I let off the gas it would finally shift into the next gear. It acts like it has just enough power to pull itself (if that)
i hav a 2007 mazda atenza.it recently went into limp mode.its had a partial rebuild with so many complications i finally have it back but when i slow down to a corner the gears dnt shift dwn to help me slow down and when i come up to a corner to stop its skips 2nd gear completely.also sometimes in revs up to 5000 revs from 1st to 2nd.the transmission place say theres nothing wrong with it but i beg to differ.can u please help.my car has been sent bak 5 times ova a period of 3 months and im so over it.thanx
I have a 2000 Chevy 1500 5.3 motor and I have owned it about 3 years had it for about 2 days and it got stolen found it three days later lucky me the only thing was wrong with it they broke the driver side window to get in use that club you know the anti-theft Club to break the ignition and off they went but when I found it it was stuck in 2 wheel drive they had to tow trucks hooked up to it trying to pull it out of the mud thank God they could not get it out because they called me so I jumped in the old PT Cruiser a cruise on over there got there first thing I asked was how much is it going to cost me to pull my truck out of the mud they told me about six or seven hundred dollars because they are having so much problems getting it out I told them get your tow truck off my truck my truck is not stuck so the police made them on hookit and I walked out there and got in my truck took me a minute to get it started but I got her running but now I’m having problems getting it in gear because the guy that stole it did not know how to put it into 4 wheel drive and the 4-wheel drive lights were blinking and the transmission would not do nothing reset computer started it back up lights blinking no more but I think the computer and the transfer case was having a hell of a time finding its gears grinding and making all kinds of noise and again 4 wheel drive light started blinking had to reset computer one more time got back in the truck started it back up but this time it went into 4 wheel drive first thing that hit my mind time to sling some mud I would say it took me a couple of times but that truck was out and that was the end of that day so in the back of my mind I kind of figured the tranny was going to go out sooner or later now I’m not for sure if it was the transmission or the transfer case grinding all those gears and yes maybe I should have took it into a tranny shop but once again I thank God that I did not because I drove that truck for just about a year after it got stolen so one day I was driving down the road doing about 40 45 maybe 50 I am a fast driver so usually it says 30 I’m doing 45 50 but anyways I drove that truck almost a year and that transmission did not skip a beat I even took it 4 wheel drive in a couple of times did not make no noise never had a problem going into 4 wheel drive and most importantly about the transmission and never slept but I was driving it down the road as I was saying and all of a sudden it jumped right out of gear so I did what any normal person would do I pulled the truck over immediately and shut her down and I know jumping out and looking underneath the truck y’all really can’t do too much for a transmission especially if it’s internal but it always makes a man feel better I guess well jump back in the truck dropped her down into drive and took off slow but now I’m really listening to the truck and transmission first gear seems to be working well went right into second gear no problem 2nd gear seems to be having no trouble and yes sir she shifted right into third and we are now cruising 45 50 oh I forgot to mention yes the computer is going crazy the engine lights on the four wheel drive keeps blinking and the gauges are going crazy first thing I thought got to get her home ASAP well back to driving down the road now I’m cruising and now I’m coming up to a red light and I have to stop as soon as I started slowing down that Trend came out of gear once again grinding making all kinds of noise instantly stop the truck and put it in Park try to put it back in Drive grinding making all kinds of noise so yes I’m thinking tranny gone shutter down started it back up and tried to put it in drive again grinding now I’m hoping that one of my gears work reverse grinding threw it down in to first gear I had a solid lock into first Hill started heading home just in first gear and I would just like to say once again that this transmission never slept and 1st gear ain’t slipping either well teen Aamco Transmission shop on my way home and said what the hell maybe I can get her fixed hold in there ran the whole story down to him and they put the truck on the machine and started checking it out come back an hour and 30 minutes into the waiting room and told me transmission is shot no good need a new one the estimate was $2,900 dollars wow well I ain’t got $2,900 dollars going to have to save up for that one so I drove it home approximately 9 miles in first gear and I parked it about three weeks later called up a mobile mechanic cuz you know what they say it’s always good to get a second opinion he came out read all the codes and told me transmission is gone to put no good need a new one ask him why it just went out just like that when it never slept never skip a beat and all he could tell me is that it happens so two days later my neighbor he’s a Certified mechanic and he told me pretty much the same thing now that is three different guys with three opinions so now the truck it’s looking like it’s definitely going to need a tranny so three months have passed by now truck has been sitting for 4 months and one of my homeboys from California come down here to Albuquerque New Mexico and he’s a Certified mechanic told him all about it and he did pretty much the same thing the three other guys did but it must be my lucky day because he said the only code he is showing is that it’s just the shifting solenoid so went down spent about a hundred bucks on transmission fluid transmission filter and of course shifter solenoid come back home put them new ones in problem solved so to everybody out there don’t ever listen to a mechanic here in Albuquerque New Mexico because they are only out to rob you blind I can understand I mechanic charging you a couple extra hundred bucks for GP but not no $2,800 dollars or is it safe to say that mechanics here in New Mexico or just straight up retarded so if you read this watch out who you take your truck or car to in New Mexico because my friend told me that transmission doesn’t even look that old well I hope this can help a lot of people out and the only thing I can say about Aamco the transmission shop they are probably making billions and robbing people blind once again I have a $2,900 estimate but when the truth came out it was roughly only a hundred bucks so look out I took my truck out for buying last night and 4 by the hell out of it and once again did not skip a beat thank you God because something told me that that did not make no sense and my friend told me the same thing
I have a jeep compass 2015 latitude 4×4, going along fine then ETC, Trac Control, and check engine light comes on. Car goes into limp mode, won’t go higher than 2000 RPM. Pull over at a repair shop, they say code thrown is large vacuum leak. Mechanic says I don’t have a large vacuum, but cleared codes and turned car off an on again a few times and it went away. Drove normal for about a week. Then same thing, driving home in 34 degree weather, 55 mph then same thing happened, had to pull over, shut the car off and on again a few times, and was able to drive back home. Code again says large vacuum leak. Then works ok for 3 days, same thing again. Read a lot of blogs about compass and patriots where people say after numerous visits to repair shops they had MAP sensors, Throttle body, throttle position sensors, multi-switch in steering column, oil filler caps replaced and still acts up after thousands in repair bills. Very frustrated. Tried calling Chrysler directly at 800-334-9200 cant get through, after touching multiple prompts for jeep owners it hangs up on you. Checked for recalls by vin. no luck there. Trying to get dealership to actually fix this under the extended warranty package I bought but my gut is they won’t.
– early Jan 2018, my Nissan Micra’s battery got drained, a service guy from Roadside Assistance came, boosted it and told me to idle it for 1.5 hrs, which I did, to recharge the battery. Next morning, limp mode! I had to tow it to a dealership garage, they did an ‘idle air volume learning prodedure’ on it, then it was ok
I have a 2001 Dodge Intrepid,. That I bought from auction. I had bought a refurbished PCM because. It wasn’t getting signal. After in installing PCM car started and drove. But notice it was stuck in 2nd gear (limp mode). Had checked on computer and came back as no signal from TCM. Not sure what to do next. So if anyone can help please help.
Is it expensive to repair this problem
I have a 2000 dodge durango, 4.7l that will start and run, but will not drive nor show im in gear on the dash. I thought I had found the problem when I found all 3 wires outside the transmission pressure sensor were touching. Ended up having to replace the sensor along with a foot or two of wire from another durango (year,model,engine all the same). Could this be the issue? Or can I reprogram the new sensor? I also had put a new cranksaft sensor in hopes that was the original issue. Or do I need to get my durango reprogrammed? It also is showing a “no bus” code in the odometer and damn near jolted me to death the last time I drove it. (like 3 months ago). fuxx, someone help me. this is all the reaching put im going to do for this shit but i promise i WILL FIGURE IT OUT. I CAN DO THIS!@!!!!@!
Can limp mode be caused by bad brakes? I need to get my brakes changed on my 2013 Nissan Cube. Everything works well until the ABS light comes on, then car goes into limp mode.
I have a 2005 grand Jeep Cherokee and it’s not is stuck in low gear and not changing
I had limp mode issues in my 2005 Dodge Dakota. After had my transmission solenoid replaced found the problem was just a loose and dirty battery terminal.
I have a 2014 Nissan Rogue that I purchased new on Jan. 2015. When without warning the car started driving very slow (limp mode perhaps). You could hear the engine running but not moving fast at all. No warning on the dash at all. Went through the diagnostic check on the dash. No check engine light, nothing. It kept reading “No Warnings” I have 82,000 miles on the car. Took it to the dealer who stated I need a new transmission. How is it possible?? The service manager said “It happens sometimes without warning. Your mileage is high also.” Really? Your comments needed and welcomed. Thank you.
I have a 03 Acura TL type S 3.2L that works find until the oil heats up the transmition didn’t work at All , no matter in what gear do I put it. Looks like is in neutral but if I kill the engine and pull the key out. And put it right away back and start the engine it will work perfect for 3 or 4 minutes and is the same thing over and over so what’s my problem or I need another transmition?
Sounds like the internal filter may be getting clogged causing lack of fluid and slipping. Then you shut it off and it takes a bit to clog back up. On the Hondas the transmission needs to be opened to change the filter
2008 Grand Caravan seems to be going into limp mode. Three times randomly in last five hundred miles. The last time i finally got a check engine light and it would not shift. Stopped car and shut it off, restarted still with check engine light and it shifted fine??? I had the transmission filter and oil and both speed sensors changed, (input/output) and it drove great until today when i got the check engine light and would not shift. What should be my next move….solenoid pack????????
I have a 99 chevy Silverado 1500 z71 4×4.While driving noticed it wasn’t shifting.Then the transmission stopped working completely.Turned truck off checked fluid level to find reading high even though none has been added.Started up and drove 100 yards and would stop again.Took a few times doing this to get home.Any advice?.
I have a 2002 honda civic and all of a sudden yesterday while we were drivinh it the transmission just acted like i had put it in neutral, i can cut tbe car off and start it back up and it will do fine for a mile maybe two then same thing happens again, and again can shut car off for just bout 10 seconds start it back and go again, what is wrong?
I have a 2002 Chevy Malibu v6, Now OUT OF THE SOME THING, THE CAR START GIVING ME A BIG THUMP WHEN drive mode is selected, and does not do that all the time.
I just bought a 98 gmc jimmy it only has 1st and 3rd gear would this be a selinod problem?
I have a 04 chevy trailblazer, I have first and reverse, I can manually shift into second. When it should shift into third it down shifts back to first. Before all this happen I was sitting and it was idling and the reduce engine power light came on. I shut it down and it was fine drove it home. Then this happened any idea what it could be. We was thing selinod, but now think maybe clutches for 3
2014 dodge diesel went into limp mode. Engine light came on. I have 1 2 3 gears only. No indication of any issues. Has 138000 km on it